ABSTRACT
Food-grade rather than synthetic or chemical flocculants are needed for microalgae harvesting by settling, if used for food products. Chitosan is effective in harvesting freshwater microalgae, but it is expensive and typically not suitable for marine microalgae like Nannochloropsis. To minimize costs for food-grade flocculation, a number of potentially important parameters are considered, including chitosan solubility and optimized chitosan-mediated flocculation of Nannochloropsis sp. BR2 by a five-factor central composite design experiment. Results show that an optical density (440 nm) of 2 (0.23 g dry weight L-1), initial pH of 6, final pH of 10, and 22 ppm chitosan with a viscosity of 1808 cP provide optimum flocculation efficiency, which is predicted to be in the range of 97.01% to 99.93%. These predictions are verified on 4.5 and 8 L Nannochloropsis sp. BR2 cultures.
ABSTRACT
A chondroitin sulfate-bone marrow (CS-BM) adhesive hydrogel was used to localize rhBMP-2 to enhance articular cartilage tissue formation. Chondrocyte pellet culture revealed that 0.1 and 1 µg/mL of rhBMP-2 enhanced sulfated-GAG content. rhBMP-2 localization within the hydrogels was investigated, and it was found that BM, CS-NHS, and rhBMP-2 levels and time affected rhBMP-2 retention. Retention was modulated from 82 to 99% over a 3-week period for the material formulations investigated. To evaluate carrier efficacy, rhBMP-2 and bovine articular chondrocytes were encapsulated within CS-BM, and biochemical evaluation revealed significant increases in total collagen production with rhBMP-2. Histological analysis revealed more robust tissue formation and greater type-II collagen production with encapsulated rhBMP-2. Subsequently, a subcutaneous culture of hydrogels revealed increased total collagen, type-II to type-I collagen ratio, and sulfated GAG in samples carrying rhBMP-2. These findings indicate the development of a multifunctional system capable of localizing rhBMP-2 to enhance repair tissue quality.
Subject(s)
Bone Marrow Cells/cytology , Bone Morphogenetic Protein 2/genetics , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Transforming Growth Factor beta/genetics , Animals , Biocompatible Materials/chemistry , Bone Marrow Cells/metabolism , Bone Morphogenetic Protein 2/metabolism , Cartilage, Articular/cytology , Cattle , Cell Adhesion , Chondrocytes/chemistry , Chondrocytes/cytology , Chondroitin Sulfates/chemistry , Collagen Type I/metabolism , Collagen Type II/metabolism , Hydrogels/chemistry , Mice , Mice, Nude , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Transforming Growth Factor beta/metabolism , Wound HealingABSTRACT
Pancreatic adenosquamous carcinoma is a rare morphological variant of pancreatic adenocarcinoma with an especially poor prognosis. The purpose of this study is to identify clinicopathologic features associated with prognosis, assess whether the percentage of squamous differentiation in pancreatic adenosquamous carcinoma is associated with an inferior prognosis, and examine the impact of adjuvant chemoradiation therapy on overall survival. Forty-five (1.2%) of 3651 patients who underwent pancreatic resection at the Johns Hopkins Hospital, Baltimore, MD, between 1986 and 2007 were identified with adenocarcinoma of the pancreas with any squamous differentiation. All pathologic specimens were re-reviewed. Statistical analyses were performed on the 38 patients amenable to adjuvant chemoradiation therapy for whom clinical outcome data could be obtained. Median age was 68 years (61% male). Sixty-one percent underwent pancreaticoduodenectomy. Median tumor size was 5.0 cm. Seventy-six percent of carcinomas were node positive, 37% were margin-positive resections, and 68% had 30% or more squamous differentiation. Median overall survival of the pancreatic adenosquamous carcinoma cohort was 10.9 months (range, 2.1-140.6 months; 95% confidence interval, 8.2-12.5 months). Adjuvant chemoradiation therapy was associated with superior overall survival in patients with pancreatic adenosquamous carcinoma (P = .005). Adjuvant chemoradiation therapy was associated with improved survival in patients with tumors 3 cm or larger and vascular or perineural invasion (P = .02, .03, .02, respectively). The proportion of squamous differentiation was not associated with median overall survival (< 30% versus > or = 30%, P = .82). Survival after pancreatic resection of pancreatic adenosquamous carcinoma is poor. Treatment with adjuvant chemoradiation therapy is associated with improved survival. The proportion of squamous differentiation in resected pancreatic adenosquamous carcinoma specimens does not appear to impact overall survival.
